Braun Mischa, Finke Carsten, Ostendorf Florian, Lehmann Thomas-Nicolas, Hoffmann Karl-Titus, Ploner Christoph J
Department of Neurology, Charité-Universitätsmedizin Berlin, Campus Virchow-Klinikum, Berlin, Germany.
Brain. 2008 Oct;131(Pt 10):2742-50. doi: 10.1093/brain/awn191. Epub 2008 Aug 29.
Conflicting theories have been advanced to explain why hippocampal lesions affect distinct memory domains and spare others. Recent findings in monkeys suggest that lesion-induced plasticity may contribute to the seeming preservation of some of these domains. We tested this hypothesis by investigating visuo-spatial associative memory in two patient groups with similar surgical lesions to the right medial temporal lobe, but different preoperative disease courses (benign brain tumours, mean: 1.8 +/- 0.6 years, n = 5, age: 28.2 +/- 4.0 years; hippocampal sclerosis, mean: 16.8 +/- 1.9 years, n = 9, age: 38.9 +/- 4.1 years). Compared to controls (n = 14), tumour patients showed a significant delay-dependent deficit in memory of colour-location associations. No such deficit was observed in hippocampal sclerosis patients, which appeared to benefit from a compensatory mechanism that was inefficient in tumour patients. These results indicate that long-standing hippocampal damage can yield significant functional reorganization of the neural substrate underlying memory in the human brain. We suppose that this process accounts for some of the discrepancies between results from previous lesion studies of the human medial temporal lobe.
关于海马体损伤为何会影响不同的记忆领域而其他领域却不受影响，人们提出了相互矛盾的理论。近期对猴子的研究发现表明，损伤诱导的可塑性可能有助于某些记忆领域看似得以保留。我们通过调查两组右侧内侧颞叶有类似手术损伤但术前病程不同的患者（良性脑肿瘤患者，平均病程：1.8±0.6年，n = 5，年龄：28.2±4.0岁；海马硬化患者，平均病程：16.8±1.9年，n = 9，年龄：38.9±4.1岁）的视觉空间联想记忆来检验这一假设。与对照组（n = 14）相比，肿瘤患者在颜色 - 位置关联记忆方面表现出显著的延迟依赖性缺陷。在海马硬化患者中未观察到此类缺陷，他们似乎受益于一种在肿瘤患者中效率不高的代偿机制。这些结果表明，长期的海马体损伤可导致人脑记忆相关神经基质的显著功能重组。我们推测这一过程解释了以往人类内侧颞叶损伤研究结果之间的一些差异。
